How often should I change my spark plugs? Refer to and use the maintenance schedule in your owner’s manual when using stock plugs. For other plugs, refer to the plug manufacturer’s recommendation.

Are there any special considerations for nitrous users? Zex has a line of spark plugs specifically designed for nitrous applications. Some claim that platinum spark plugs should not be used in vehicles equipped with nitrous.

Which type produces the most power? This is a hotly debated topic with few consistencies. Conventional wisdom says that copper spark plugs produce more power than the longer life platinum or the newer iridium. In the end, there really is no concrete evidence one way or the other as any dyno testing of spark plugs results in differences that are far less than the dyno tolerances from run to run.

What is the gap specification for my plugs? Refer to your owners manual. In the case of some iridium plugs and certain plugs by other manufacturers, they will come pre-gapped. These certain type of plugs are not designed to by gapped by the end user. This post is very informative on proper spark plug gapping theory.

How do I gap my plugs? To decrease the gap, tap the ground electrode onto a hard surface. This should be a slow process as you are removing thousandths of an inch. Too hard a tap to start off with could damage the center electrode. To increase gap, use gapping wire or feeler gauges. Many parts stores also sell cheap 99¢ circular spark plug gap key chains. These should be avoided as they leave a slight angle to your gap. For the ultimate gapping tool, Jacobs Electronics makes a professional gapping tool. Some manufacturers’ spark plugs are not designed or intended to be gapped. If you purchase one of these types, do not re-gap these plugs to factory specifications!